This summer, I took my two sons and my nephew to the Frontiers of Flight Museum at Love Field Airport in Dallas.

If you like airplanes half as much as I do, you will want to visit Frontiers of Flight next time you are in the Dallas area. The exhibits cover the entire history of human flight, from Leonardo da Vinci’s sketches to the current space program. What sets this flight museum apart from most others is the sheer number of real planes on display; an aircraft enthusiast could easily spend all day there learning and exploring, and every time I visit, there seems to be something new to see.

The best piece of all is the Apollo capsule. This is not a replica. It is the actual command module from the Apollo 7 mission. That fact in itself is enough to make me stand silently for a few moments every time I visit, and reflect on the audacity of the human spirit. Three human beings sat in that very box for eleven days, the rude metal cone hurtling through the vacuum of space at 50,000 miles per hour, guided by a primitive calculating machine with far less power than any cellphone you can buy today. Their courage and skill paved the way for the triumphant moment a year later, when an air-breathing mammal from Earth set foot on the dusty, airless surface of the Moon with the unforgettable words “one small step for a man; one giant leap for mankind.”

The Apollo capsule represents something that makes me proud to be a man. That’s why it makes me sad when a student asks me if the moon landings were real – because they read some silly web page (written by someone too ordinary to capture anyone’s attention without capitalizing on fear, distrust, and ignorance) about how the whole space program was faked.

The Apollo program was a giant leap for humankind. It was a gigantic push, by a nation of dreamers, to go where no one had gone before, to do the impossible. It took a decade and cost $25 billion, which sounds like a lot of money until you compare it with the amount we spend on other kinds of hardware from stealth bombers to aircraft carriers (if you care to research this, make sure you look at operating costs, not just cost to build). And I have no doubt whatsoever that Apollo was a genuine program that delivered genuine results – among the most spectacular results ever achieved by any human enterprise. The reason for my lack of doubt is called Occam’s Razor.

Occam’s Razor is a general rule of logic, the idea being that when you have to choose between a number of explanations, the simplest one – the explanation that requires the fewest assumptions to support it – is the most reliable.

There are many websites devoted to the idea that the Apollo moon missions – if not the entire U.S. space program – were a hoax. I will not list all the arguments here; you can find them easily enough if you are interested (or more likely, if you are really bored). The most obvious weakness of these theories is that they fail the test of Occam’s Razor. They depend on many more assumptions without evidence to support them – let alone the fact that they fail to explain how GPS works if we never went into space. But the thing that annoys me the most about these people is the way they disrespect all the courageous astronauts who risked their lives – and a few who lost their lives – for the sake of lifting a nation’s eyes and spirits to the stars. I wonder if they would have the nerve to look Buzz Aldrin in the face and call him a liar. Somehow I doubt it.